Light and Frost tested a 70 cm mast with vortex generators(vg) mounted on both sides of the mast in flat water to extremely rough beach breaks and chop.
First no negative effects were seen. Further comparative tests were run with two(2) Speed II 19 meter kites on flat water. Both kites' line lengths were tuned with larkshead extensions on the lines to return to factory setting and both riders flew both kites to cross-check for kite function. One rider was using a 7ft Naish directional which until the advent of race boards always was the first on the water going upwind as wind speeds increased. During this test wind speed was just enough to fly the kite without constant back stall. The very small surfboard mounted with the 70cm mast, vg and a small wing set ran rings around the 7ft Naish surfboard. This does not prove a positive effect of the vg installed mast but it does show that there were no negative effects. The board was kept in a sub planning mode just off the water with the aft thrusters and tail just touching the water. The 7ft Naish board would hardly move across the water while the small hydrofoil surfboard flew back and forth around the 7ft surfboard. Hence vagaries in wind speed were not a factor as both test vehicles were in close geographic proximity at the same time.
Furthermore the vg seemed to dampen the wobble as the board climbs off the water onto the wings. In several cases in highly overpowered conditions the kite was flown directly overhead. The board climbed off the water surface on the foil and very little foot steering was required to keep the board riding in a straight line.
From the perspective of cost, making these vg is no more expensive then a cup of coffee. A small aluminum Tee-bar was found in an air conditioning shop. The Tee-bar was cut into 0.5 cm sections and shaped with a metal file. The vg were mounted using superglue much like an aviation installation at 10cm intervals. Each vg pair was set at a 15 degree angle to a 90 degree line against the mast. With respect to superglue, the glue was applied in two stages as follows.
To repair dents and cracks in airplane propellers to include surfboard dents, superglue can be used. First fill the dent with superglue, then sprinkle finely ground Sodium Bicarbonate(Baking Soda) on the surface of the glue. The glue instantly hardens 5 times stronger then normal superglue. Next brush off the excess Baking Soda with a brush then file or wet sand. If the void is not filled apply the process again until void has been removed. What is important here is the hardness
To install the vg first apply superglue to the vg base and affix to the mast. Once dry apply superglue to the edges of the vg base and sprinkle baking soda on the glue then file around the base flat if required
If you wish to remove these vg use acetone(nail polish remover) to dissolve the glue.
Currently a 90cm mast is being tested on a heavy 7ft surfboard. The board will be tested without vg then vg will be installed and comparative tests conducted.
Small vg are being designed for the wing. These tests will also follow
For further reading see
http://www.ije.ir/abstract/%7BVolume:28 ... 2%7D/=1891
Light and Frost